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Advanced Quantum-Nano Materials & Optoelectronics Laboratory
 
 

QR code_Prof. Jihoon Lee

Kwangwoon Univ. KOR ver website

Kwangwoon Univ. Eng ver website

Kwangwoon College of Electronics and Informattion Engineering

Dept. of Electronics and Communications Engineering

 

University of Arkansas


Sam M. Walton College of Business

 

ERC 선도연구센터

BK 21 PLUS

Engineering Research Center, Holo-Digilog Human Media

Ministry of Science, ICT and Future Planning

Ministry Of Education

NIPA

KCC

Ministry of Education, Science and Technology

ITRC logo

ITRC Forum 2011

 

 

- Journal Editor -

3D Research

NRL cover

 

 

- Research Highlight -

 

Journal Cover: Precise Control of Configuration, Size and Density of Self-assembled Au Nanostructures on 4H-SiC (0001) by Systematic Variation of Deposition Amount, Annealing Temperature and Duration

(Journal cover,
CrystEngComm)
Volume 18
Issue 19

(2016)

Journal cover,CrystEngComm Volume 16 Issue 21 (2014)

(Journal cover,
CrystEngComm)
Volume 16
Issue 21

(2014)

 

Physica Status Solidi (a)) Volume 209 issue 6

(Journal cover,
Physica Status Solidi (a))
Volume 209
Issue 6

(2012)

 

Journal cover, Physica Status Solidi (a) Volume 208 Issue 1 (2011)

(Journal cover,
Physica Status Solidi (a))
Volume 208
Issue 1

(2011)

 

( Journal cover, IEEE Transactions on Nanotechnology) Volume 9 Issue 2  (2010)
( Journal cover,
IEEE Transactions on Nanotechnology)
Volume 9
Issue 2

(2010)

 

Wiley's Material Science online portal, Materials Views

(Materials Views, Wiley's Material Science)
"Nano Rings and Nano Pyramids"
(2010)

 


(Journal cover, Physica Status Solidi (a)) Volume 207 Issue 2  (2010)
(Journal cover,
Physica Status Solidi (a))
Volume 207
Issue 2

(2010)

 

(Journal cover, Applied Physics Letters) Volume 89 Issue 20  (2006)
(Journal cover,
Applied Physics Letters)
Volume 89
Issue 20

(2006)

 



(2006 MRS Fall Meeting Scene)
"Self-Assembly of InGaAs Quantum Dot Molecules (QDMs)"
(2006)

 

(Journal cover, Applied Physics Letters) Volume 88 Issue 23  (2006)

(Journal cover,
Applied Physics Letters)
Volume 88
Issue 23

(2006)

 

www.nanowerk.com

(NanoWerk, Spotlight)
"Quantum dot necklaces and other QD chains"
(April 12, 2006)

 

 


- PUBLICATIONS -

Journal Papers


* AUTHORS (in the order of authorship)
** TYPE: A: article, B: full book, CB: chapter of book, E: editor, & R: review, V: Video journal
***
IF: ISI® impact factor
*** Trend of Impact Factor of journals with interest (JCR IF 2015
)

 

TITLE: Nanoparticles to Nanoholes: Fabrication of Porous GaN with Precisely Controlled Dimension via the Enhanced GaN Decomposition by Au nanoparticles
AUTHORS: P. Pandey, M. Sui, M. Y. Li, Q. Zhang, S. Kunwar,
J. Wu, Z. M. Wang, G. J. Salamo and J. H. Lee
JOURNAL/BOOK TITLE:
Crystal Growth & Design
VOLUME:                                  FIRST PAGE:
YEAR OF PUBLICATION:
2016                              KEY: A                      IF: 4.891


Abstract


 

Porous GaN exhibits unique optoelectronic, chemical, and physical properties such as shift of band gap, increased surface area ratio, excellent chemical, mechanical, and thermal stability as well as efficient luminescence as compared to its bulk counterpart. Herein, we demonstrate a precise, efficient, and still cost-effective method of the fabrication of porous GaN through the enhanced GaN decomposition by using Au nanoparticles (NPs) as a catalyst, in which the size, density, and shape of the pores (nanoholes, NHs) can be precisely controlled. By the thermal annealing assisted with the Au NPs, the NHs are successfully fabricated, and the existence of Au NPs significantly accelerate the GaN decomposition at the interface between the NPs and GaN due to the Ga absorption by the Au NPs. We systematically study the formation mechanism of NHs assisted by the Au NPs by means of annealing temperature, duration, and Au deposition amount, and the results are systematically analyzed and discussed.

 

Graphical Abstract



Nanoparticles to Nanoholes: Fabrication of Porous GaN with Precisely Controlled Dimension via the Enhanced GaN Decomposition by Au nanoparticles

Nanoparticles to Nanoholes: Fabrication of Porous GaN with Precisely Controlled Dimension via the Enhanced GaN Decomposition by Au nanoparticles

 

 


 

TITLE: Journal Cover: Precise Control of Configuration, Size and Density of Self-assembled Au Nanostructures on 4H-SiC (0001) by Systematic Variation of Deposition Amount, Annealing Temperature and Duration
AUTHORS: M. Y. Li, M. Sui,P. Pandey, Q. Zhang, S. Kunwar, G. J. Salamo and J. H. Lee
JOURNAL/BOOK TITLE:
CrystEngComm
VOLUME: 18                                  FIRST PAGE: 3347
YEAR OF PUBLICATION:
2016                              KEY: A                      IF: 4.043
Journal Cover: Precise Control of Configuration, Size and Density of Self-assembled Au Nanostructures on 4H-SiC (0001) by Systematic Variation of Deposition Amount, Annealing Temperature and Duration

 

 

 

TITLE: Precise Control of Configuration, Size and Density of Self-assembled Au Nanostructures on 4H-SiC (0001) by Systematic Variation of Deposition Amount, Annealing Temperature and Duration
AUTHORS:
M. Y. Li, M. Sui,P. Pandey, Q. Zhang, S. Kunwar, G. J. Salamo and J. H. Lee
JOURNAL/BOOK TITLE:
CrystEngComm
VOLUME: 18                                 FIRST PAGE: 3347
YEAR OF PUBLICATION:
2016                              KEY: A                      IF: 4.043


Abstract


 

The precise control over the configuration, size and density of Au nanoparticles (NPs) has offered an efficient route to enhance and optimize the performance and usability of various NP-based applications. In this study we successfully demonstrate the precise control of configuration, size and density of the self-assembled Au nanostructures on 4H-SiC (0001) via the systematic variation of deposition amount, annealing temperature and duration. Depending on the deposition amount at fixed annealing temperature and duration, the self-assembled Au NPs are successfully fabricated based on the Volmer-Weber growth model, and the NPs nucleate as round-dome shape and evolve into the hexagonal nano-crystals with the facet formation along with the increased deposition amounts. For the variation of annealing temperatures, the Au nanostructures radically develope into two distinct regimes: i.e. irregular Au nano-mounds (Regime I) between 400 and 700 °C based on the diffusion limited agglomeration (DLA) model and round-dome shaped droplets (DPs) (Regime II) between 750 and 900 °C. Depending on the dwelling time, the size and density evolution of round-dome shape Au DPs are dicusscussed based on the Ostwald-ripening theory.

 

Graphical Abstract



Precise Control of Configuration, Size and Density of Self-assembled Au Nanostructures on 4H-SiC (0001) by Systematic Variation of Deposition Amount, Annealing Temperature and Duration

Precise Control of Configuration, Size and Density of Self-assembled Au Nanostructures on 4H-SiC (0001) by Systematic Variation of Deposition Amount, Annealing Temperature and Duration

 

 

TITLE: Au-assisted Fabrication of Nano-holes on c-plane Sapphire via Thermal Treatment guided by Au Nanoparticles as Catalysts
AUTHORS: M. Sui, P. Pandey, M. Y. Li, Q. Zhang, S. Kunwar and J. H. Lee
JOURNAL/BOOK TITLE:
Applied Surface Science
VOLUME: 392                                 FIRST PAGE:
YEAR OF PUBLICATION:
2016                              KEY: A                      IF: 3.15


Abstract


 

Nanoscale patterning of sapphires is a challenging task due to the high mechanical strength, chemical stability as well as thermal durability. In this paper, we demonstrate a gold droplet assisted approach of nano-hole fabrication on c-plane sapphire via a thermal treatment. Uniformly distributed nano-holes are fabricated on the sapphire surface guided by dome shaped Au nanoparticles (NPs) as catalysts and the patterning process is discussed based on the disequilibrium of vapor, liquid, solid interface energies at the Au NP/sapphire interface induced by the Au evaporation at high temperature. Followed by the re-equilibration of interface energy, transport of alumina from the beneath of NPs to the sapphire surface can occur along the NP/sapphire interface resulting in the formation of nano-holes. The fabrication of nano-holes using Au NPs as catalysts is a flexible, economical and convenient approach and can find applications in various optoelectronics.

 

Graphical Abstract



 

Au-assisted Fabrication of Nano-holes on c-plane Sapphire via Thermal Treatment guided by Au Nanoparticles as Catalysts

Au-assisted Fabrication of Nano-holes on c-plane Sapphire via Thermal Treatment guided by Au Nanoparticles as Catalysts

 

 

TITLE: Metallic Nanodroplet Induced Coulomb Catalysis for Off-Resonant Plasmonic Enhancement of Photoemission in Semiconductors
AUTHORS: Arup Neogi, Karol Gryczynski, Antonio Llopis, Jie Lin, Kyle Main, Ryoko Shimada, Zhiming Wang, Jihoon Lee, Gregory Salamo, and Arkadii Krokhin
JOURNAL/BOOK TITLE:
ACS Omega
VOLUME: 1                                 FIRST PAGE: 19
YEAR OF PUBLICATION:
2016                              KEY: A  


Abstract


 

The enhancement of light from semiconductors due to surface plasmons coupled resonantly to its emission is limited because of dissipation in the metal and is also restricted by the dielectric characteristics and homogeneity of the metal−semiconductor interface. We report a new mechanism based on electrostatic interactions of carriers and their image charges in metals to generate more photons from optical sources at frequencies that are off-resonant to the localized plasmon frequency. Coulomb catalysis of carrier accumulation resulting from the inhomogeneity of metal nanodroplets on a semiconductor’s surface can result in an enhancement of light that is nondissipative and does not require resonant coupling of plasmons to the emission wavelength. The enhancement occurs because of an increase in the ratio of radiative to nonradiative recombination in the vicinity of metal nanoparticles. It is equally effective with any type of metal and enhances radiation at any frequency, a property that is of principal importance for the realization of widely tunable semiconductor emitters. This fundamental mechanism provides a new perspective for improving the efficiency of light emitters and controlling carrier concentration on the nanoscale. The structural characteristics of the hybrid metal−semiconductor emitters are studied using electron microscopy and atomic force microscopy. We demonstrate the electrostatic mechanism by studying steady-state and transient photoluminescence from two-dimensional semiconductors, such as GaAs/AlGAs quantum wells, and bulk semiconductors, such as ZnO thin films, emitting in the near-IR and UV wavelength regimes, respectively.

 

Graphical Abstract



Metallic Nanodroplet Induced Coulomb Catalysis for Off-Resonant Plasmonic Enhancement of Photoemission in Semiconductors

Metallic Nanodroplet Induced Coulomb Catalysis for Off-Resonant Plasmonic Enhancement of Photoemission in Semiconductors

Metallic Nanodroplet Induced Coulomb Catalysis for Off-Resonant Plasmonic Enhancement of Photoemission in Semiconductors

 

 

 

TITLE: Systematic Control of the Size, Density and Configuration of Pt Nanostructures on Sapphire (0001) by the Variation of Deposition Amount and Dwelling Time
AUTHORS: P. Pandey, M. Sui, Q. Zhang, M. Y. Li, S. Kunwar and J. H. Lee
JOURNAL/BOOK TITLE:
Applied Surface Science
VOLUME: 368                                 FIRST PAGE: 198
YEAR OF PUBLICATION:
2016                              KEY: A                      IF: 3.15


Abstract


 

Metal nanoparticles (NPs) with controllable size, density and configuration can significantly enhance the energy conversion efficiency, detection sensitivity and catalytic activity as witnessed in various optoelectronic, optical sensing and electro-catalytic devices due to their shape and size dependent properties. In this work, we systematically investigate the evolution of the size, density and configuration of Pt nanostructures on sapphire (0001). In particular, we have demonstrated four different configuration and evolution of Pt nanostructures with the systematic control of deposition amount (DA) based on the Volmer-Weber growth model in conjunction with the surface energy minimization mechanism, diffusion and coalescence. The various size and configuration of Pt nanostructures with respect to DA are (i) nucleation of mini-sized round shaped Pt NPs (1 ≤ DA ≤ 5 nm), (ii) growth of large sized Pt NPs (10 ≤ DA ≤ 15 nm), (iii) isolated irregular nanostructures (20 ≤ DA ≤ 30 nm) and (iv) coalesced Pt nanostructures (DA ≥ 40). On the other hand, with the increased dwelling time (DT), irregular Pt NPs are fabricated with the increased size and improved uniformity between 0 and 450 s of annealing. The growth of Pt NPs is saturated when the dwelling time reaches the critical value between 900 and 1800 s, which can be attributed to the Ostwald ripening.

 

Graphical Abstract



Systematic Control of the Size, Density and Configuration of Pt Nanostructures on Sapphire (0001) by the Variation of Deposition Amount and Dwelling Time

Systematic Control of the Size, Density and Configuration of Pt Nanostructures on Sapphire (0001) by the Variation of Deposition Amount and Dwelling Time

 

 

 

TITLE: Optical Properties of a Quantum Dot-Ring System Grown Using Droplet Epitaxy
AUTHORS: Gabriel Linares-García, Lilia Meza-Montes, Eric Stinaff, S. M. Alsolamy, M. E. Ware, Y. I. Mazur, Z. M. Wang, Jihoon Lee and G. J. Salamo
JOURNAL/BOOK TITLE:
Nanoscale Research Letters
VOLUME: 
11                                 FIRST PAGE: 309
YEAR OF PUBLICATION:
2016                              KEY: A                      IF: 2.779


Abstract


 

Electronic and optical properties of InAs/GaAs nanostructures grown by the droplet epitaxy method are studied. Carrier states were determined by k·p theory including effects of strain and In gradient concentration for a model geometry. Wavefunctions are highly localized in the dots. Coulomb and exchange interactions are studied and we found the system is in the strong confinement regime. Microphotoluminescence spectra and lifetimes were calculated and compared with measurements performed on a set of quantum rings in a single sample. Some features of spectra are in good agreement.

 

Graphical Abstract



 

Optical Properties of a Quantum Dot-Ring System Grown Using Droplet Epitaxy


Optical Properties of a Quantum Dot-Ring System Grown Using Droplet Epitaxy

 

 

 

TITLE: Tuning the Configuration of Au Nanostructures: From Vermiform-like, Rod-like, Triangular, Hexagonal, to Polyhedral Nanostructures on c-plane GaN
Full Text Access: http://rdcu.be/j3CD
AUTHORS: M. Sui, P. Pandey, M. Y. Li, Q. Zhang, S. Kunwar
and J. H. Lee
JOURNAL/BOOK TITLE:
Journal of Material Science
VOLUME: 51                                  FIRST PAGE: 1 - 17

YEAR OF PUBLICATION:
2016                              KEY: A                      IF: 2.302


Abstract


 

The systematic control over the configuration, size and density of Au nanostructures can directly improve or optimize the physical, chemical and optoelectronic properties and thus the functionality in the related applications. In this work, we successfully demonstrate the systematic configurational transition of self-assembled Au nanostructures on c-plane GaN via the precise control of annealing temperature, deposition amount and annealing duration. Depending on the control of annealing temperature, self-assembled Au vermiform-like nanostructures are fabricated and evolve into the faceted Au nanorods and Au hexagons with the minimization of overall surface energy based on the Volmer-Weber growth model. With the deposition amount control, the volume-dependent transition of Au nanostructure configurations from triangles to hexagons and then to polyhedral is clearly observed and discussed based on the combinational effects of growth kinetics and surface free energy distribution. The configurational transition from irregular Au clusters to faceted nanostructures is witnessed along with the incremental variation of annealing duration based on the Ostwald-ripening.

 

Graphical Abstract



Tuning the Configuration of Au Nanostructures: From Vermiform-like, Rod-like, Triangular, Hexagonal, to Polyhedral Nanostructures on c-plane GaN

Tuning the Configuration of Au Nanostructures: From Vermiform-like, Rod-like, Triangular, Hexagonal, to Polyhedral Nanostructures on c-plane GaN

 

 

 

TITLE: From the Au nano-clusters to the nanoparticles on 4H-SiC (0001)
AUTHORS: M. Y. Li, Q. Zhang,P. Pandey, M. Sui, E. S. Kim and J. H. Lee
JOURNAL/BOOK TITLE:
Scientific Reports
VOLUME: 5                                  FIRST PAGE: 13954
YEAR OF PUBLICATION:
2015                              KEY: A                      IF: 5.578


Abstract


 

The control over the configuration, size, and density of Au nanoparticles (NPs) has offered a promising route to control the spatial confinement of electrons and photons, as a result, Au NPs with a various configuration, size and density are witnessed in numerous applications. In this work, we investigate the evolution of self-assembled Au nanostructures on 4H-SiC (0001) by the systematic variation of annealing temperature (AT) with several deposition amount (DA). With the relatively high DAs (8 and 15 nm), depending on the AT variation, the surface morphology drastically evolve in two distinctive phases, i.e. (I) irregular nano-mounds and (II) hexagonal nano-crystals. The thermal energy activates adatoms to aggregate resulting in the formation of self-assembled irregular Au nano-mounds based on diffusion limited agglomeration at comparatively low annealing temperature, which is also accompanied with the formations of hillocks and granules due to the dewetting of Au films and surface reordering. At high temperature, hexagonal Au nano-crystals form with facets along {111} and {100} likely due to anisotropic distribution of surface energy induced by the increased volume of NPs. With the small DA (3 nm), only dome shaped Au NPs are fabricated along with the variation of AT from low to elevated temperature.

 

Graphical Abstract



From the Au nano-clusters to the nanoparticles on 4H-SiC (0001)

From the Au nano-clusters to the nanoparticles on 4H-SiC (0001)

 

 

 

TITLE: Systematic Study on the Self-assembled Hexagonal Au Voids, Nano-clusters and Nanoparticles on GaN (0001)
AUTHORS: P. Pandey, M. Sui, M. Y. Li, Q. Zhang, E. S. Kim and J. H. Lee
JOURNAL/BOOK TITLE:
PLOS ONE
VOLUME: 10(8)
                                  FIRST PAGE: e0134637
YEAR OF PUBLICATION:
2015                              KEY: A                      IF: 3.324


Abstract


 

Au nano-clusters and nanoparticles (NPs) have been widely utilized in various electronic, optoelectronic, and bio-medical applications due to their great potentials. The size, density and configuration of Au NPs play a vital role in the performance of these devices. In this paper, we present a systematic study on the self-assembled hexagonal Au voids, nano-clusters and NPs fabricated on GaN (0001) by the variation of annealing temperature and deposition amount. At relatively low annealing temperatures between 400 and 600 oC, the fabrication of hexagonal shaped Au voids and Au nano-clusters are observed and discussed based on the diffusion limited aggregation model. The size and density of voids and nano-clusters can systematically be controlled. The self-assembled Au NPs are fabricated at comparatively high temperatures from 650 to 800 oC based on the Volmer-Weber growth model and also the size and density can be tuned accordingly. The results are symmetrically analyzed and discussed in conjunction with the diffusion theory and thermodynamics by utilizing AFM and SEM images, EDS maps and spectra, FFT power spectra, cross-sectional line-profiles and size and density plots.

 

Graphical Abstract



Systematic Study on the Self-assembled Hexagonal Au Voids, Nano-clusters and Nanoparticles on GaN (0001)

Systematic Study on the Self-assembled Hexagonal Au Voids, Nano-clusters and Nanoparticles on GaN (0001)

 

 

 

TITLE: Systematic Control of Self-Assembled Au Nanoparticles and Nanostructures Through the Variation of Deposition Amount, Annealing Duration, and Temperature on Si (111)
AUTHORS:
M. Y. Li, M. Sui,P. Pandey, Q. Zhang, E. S. Kim and J. H. Lee
JOURNAL/BOOK TITLE:
Nanoscale Research Letters
VOLUME:  
10                                FIRST PAGE: 494
YEAR OF PUBLICATION:
2015                              KEY: A                      IF: 2.779


Abstract


 

The size, density, and configurations of Au nanoparticles (NPs) can play important roles in controlling the electron mobility, light absorption, and localized surface plasmon resonance, and further in the Au NP-assisted nanostructure fabrications. In this study, we present a systematical investigation on the evolution of Au NPs and nanostructures on Si (111) by controlling the deposition amount (DA), annealing temperature (AT), and dwelling time (DT). Under an identical growth condition, the morphologies of Au NPs and nanostructures drastically evolve when the DA is only slightly varied, based on the Volmer-Weber and coalescence models: i.e. I: mini NPs, II: mid-sized round dome-shaped Au NPs, III: large Au NPs, and IV: coalesced nanostructures. With the AT control, three distinctive ranges are observed: i.e., NP nucleation, Au NPs maturation and melting. The gradual dimensional expansion of Au NPs is always compensated with the density reduction, which is explained with the thermodynamic theory. The DT effect is relatively minor on Au NPs, a sharp contrast to other metallic NPs, which is discussed based on the Ostwald-ripening.

 

Graphical Abstract



Systematic Control of Self-Assembled Au Nanoparticles and Nanostructures Through the Variation of Deposition Amount, Annealing Duration, and Temperature on Si (111)

Systematic Control of Self-Assembled Au Nanoparticles and Nanostructures Through the Variation of Deposition Amount, Annealing Duration, and Temperature on Si (111)

 

 

 

TITLE: Diamagnetic and paramagnetic shifts in self-assembled InAs lateral quantum dot molecules
AUTHORS:
Xinran Zhou, Miquel Royo, Weiwen Liu, Jihoon H. Lee, Gregory. J. Salamo, Juan I. Climente, and Matthew F. Doty
JOURNAL/BOOK TITLE:
Physical Review B
VOLUME: 91                                 FIRST PAGE: 205427
YEAR OF PUBLICATION:
2015                              KEY: A                      IF: 3.664


Abstract


 

We uncover the underlying physics that explains the energy shifts of discrete states of individual InAs lateral quantum dot molecules (LQDMs) as a function of magnetic fields applied in the Faraday geometry. We observe that ground states of the LQDM exhibit a diamagnetic shift while excited states exhibit a paramagnetic shift. We explain the physical origin of the transition between these two behaviors by analyzing the molecular exciton states with effective mass calculations. We find that charge carriers in delocalized molecular states can become localized in single QDs with increasing magnetic field. We further show that the net effects of broken symmetry of the molecule and Coulomb correlation lead to the paramagnetic response.

 

Graphical Abstract



Diamagnetic and paramagnetic shifts in self-assembled InAs lateral quantum dot molecules

Diamagnetic and paramagnetic shifts in self-assembled InAs lateral quantum dot molecules

 

 

 

TITLE: Evolution of Self-Assembled Au NPs by controlling Annealing Temperature and Dwelling Time on Sapphire (0001)
AUTHORS: J. H. Lee, P. Pandey, M. Sui, M. Y. Li, Q. Zhang and S. Kunwar
JOURNAL/BOOK TITLE:
Nanoscale Research Letters
VOLUME:  10                                FIRST PAGE: 380
YEAR OF PUBLICATION: 2015                              KEY: A                      IF:
2.779


Abstract


 

Au nanoparticles (NPs) have been utilized in a wide range of device applications as well as catalysts for the fabrication of nanopores and nanowires, in which the performance of the associated devices and morphology of nanopores and nanowires are strongly dependent on the size, density and configuration of the Au NPs. In this paper, the evolution of self-assembled Au nanostructures and NPs on sapphire (0001) is systematically investigated with the variation of annealing temperature (AT) and dwelling time (DT). At the low temperature range between 300 and 600 oC, three distinct regimes of the Au nanostructure configuration are observed i.e. the vermiform-like Au piles, irregular Au nano-mounds and Au islands. Subsequently, being provided with relatively high thermal energy between 700 to 900 oC, the round dome shaped Au NPs are fabricated based on the Volmer-Weber growth model. With the increased AT, the size of the Au NPs is gradually increased due to more favorable surface diffusion while the density is gradually decreased as a compensation. On the other hand, with the increased DT, the size and density of Au NPs decreases due to the evaporation of Au at relatively high annealing temperature at 950 oC.

 

Graphical Abstract



Evolution of Self-Assembled Au NPs by controlling Annealing Temperature and Dwelling Time on Sapphire (0001)

Evolution of Self-Assembled Au NPs by controlling Annealing Temperature and Dwelling Time on Sapphire (0001)

 

 

 

TITLE: Shape transformation of self-assembled Au nanoparticles by the systematic control of deposition amount on Sapphire (0001)
AUTHORS: P. Pandey, M. Sui, M. Y. Li, Q. Zhang, E. S. Kim and J. H. Lee
JOURNAL/BOOK TITLE:
RSC Advances
VOLUME: 5                                 FIRST PAGE: 66212
YEAR OF PUBLICATION:
2015                              KEY: A                      IF: 3.840


Abstract


 

The shape and size dependent optical, physical and chemical properties of isotropic and anisotropic gold nanoparticles (Au NPs) have attracted significant research interests for the applications in various optoelectronic devices. In this paper, we systematically study the evolution of shape and size of self-assembled Au NPs by the variation of Au deposition amount on Sapphire (Al2O3) (0001). With the sufficient thermal energy (1000 oC) provided, dome shape Au NPs are fabricated on sapphire based on the Volmer-Weber growth model, due to the isotropic surface energy distribution. Furthermore, we observe the incremental variation of Au deposition amount is responsible for the transformation of isotropic to anisotropic Au nanoparticles (nanocrystals). An anisotropic nanoparticles reflect variant properties in their different crystalline surfaces and thus the utilization of anisotropic nanoparticles can lead to the comparatively high efficiency of related device applications. The addition of Au deposition amount leads to the facet formation on the lowest possible energy crystalline planes of NPs such that the orientation of top facet of Au NPs are (111) plane parallel to the (0001) plane of sapphire. However, due to many other higher index facet formation, the NPs look almost dome shaped at high amount of Au deposition. Overall, the shape transformation of NPs from dome, truncated hexagonal pyramid, elongated truncated hexagonal pyramid, truncated cone to multifaceted dome is observed along with the variation of Au deposition amount on Sapphire (Al2O3) (0001).

 

Graphical Abstract



Shape transformation of self-assembled Au nanoparticles by the systematic control of deposition amount on Sapphire (0001)

Shape transformation of self-assembled Au nanoparticles by the systematic control of deposition amount on Sapphire (0001)

 

 

 

TITLE: Configuration, Dimension and Density Control of 3-D Gold Nanostructures on various Type-B GaAs surfaces by the Systematic Variation of Annealing Temperature, Annealing Duration and Deposition Amount
AUTHORS: D Lee, M. Sui, M. Y. Li, P. Pandey, Q. Zhang,
E. S. Kim and J. H. Lee
JOURNAL/BOOK TITLE:
3D Research
VOLUME:  
6                                FIRST PAGE: 28(1) - 28(14)
YEAR OF PUBLICATION:
2015                              KEY: A


Abstract


 

Metallic nanoparticles have received extensive research attention due to their potential to be utilized in catalytic, electronic and optical applications. Tunable feature of quantum effect related to the configuration, dimension as well as the density of nanoparticles makes them appropriate building blocks for their applications at the nano-scale. In this paper, we systematically investigate the fabrication of self-assembled Au nanoparticles on high–index type-B GaAs (n11), where n is 9, 8, 4, and 2. By means of varying annealing temperature, Au deposition amount and annealing duration, the evolution of Au nanoparticles in terms of the average height, lateral diameter and average density is systematically studied. We observe that the variation of annealing temperature leads to an abrupt configuration evolution from the wiggly Au nanostructures to the round-dome shaped nanoparticles due to the limited and/or enhanced surface diffusion at various temperatures. Meanwhile, the variation of deposition amount leads to a wide range of dimensions of Au nanoparticles as a result of the size increase and the corresponding density decrease. Furthermore, based on the annealing duration control, the size of Au nanoparticles tends to be gradually increased owing to the Ostwald-ripening. Meanwhile, the effect of surface index on the size and density is also witnessed. The results are systematically analyzed by using the atomic force microscope images, energy-dispersive X-ray spectroscopy spectra and maps, Fourier filter transforms power spectra, cross-sectional line-profiles and size and density plots.

 

Graphical Abstract



Configuration, Dimension and Density Control of 3-D Gold Nanostructures on various Type-B GaAs surfaces by the Systematic Variation of Annealing Temperature, Annealing Duration and Deposition Amount

Configuration, Dimension and Density Control of 3-D Gold Nanostructures on various Type-B GaAs surfaces by the Systematic Variation of Annealing Temperature, Annealing Duration and Deposition Amount

 

 

 

TITLE: Observation of Shape, Configuration, and Density of Au Nanoparticles on Various GaAs Surfaces via Deposition Amount, Annealing Temperature, and Dwelling Time
AUTHORS: D. Lee, M. Y. Li,
M. Sui, Q. Zhang, P. Pandey, E. S. Kim and J. H. Lee
JOURNAL/BOOK TITLE:
Nanoscale Research Letters
VOLUME:  
10                                FIRST PAGE: 240
YEAR OF PUBLICATION:
2015                              KEY: A                      IF:2.779


Abstract


 

Metallic nanoparticles have been widely witnessed in many applications: serving as the catalysts for various nanowire systems, as the active mediums of various device applications, and also for the nanoscale templates for hybrid quantum structures. In the performance of devices and configurations of the resulting nanostructures, the size and density of nanoparticles play critical roles. In this paper, the control of self-assembled Au droplets on GaAs (100), (110), and (111) is systematically investigated through the variation of deposition amount (DA), annealing temperature (AT), and dwelling time (DT). Based on the
Volmer–Weber growth model, the formation of Au droplets and dramatic evolution of Au nanostructures on various GaAs surfaces is observed from the Au clusters to the round-dome shapes with the AT variation between 250 and 550 °C. With the systematic DA control, a radical size and density evolution of Au droplets shows the size expansion of over 400 % in average height and 800 % in average lateral diameter, while the density shows over two orders of decrease. With the DT variation, the self-assembled Au droplets tend to grow larger due to the Ostwald ripening while a clear distinction among the surface indexes is observed.

 

Graphical Abstract



Observation of Shape, Configuration, and Density of Au Nanoparticles on Various GaAs Surfaces via Deposition Amount, Annealing Temperature, and Dwelling Time

Observation of Shape, Configuration, and Density of Au Nanoparticles on Various GaAs Surfaces via Deposition Amount, Annealing Temperature, and Dwelling Time

 

 

 
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